


the rush that comes with your embrace

by deviancy



Category: Undertale (Video Game)
Genre: Cunnilingus, Electrical Play, F/M, Male Mettaton, Mild S&M, Object Insertion, Overstimulation, Robot Kink, Robot Sex, Vaginal Fisting, heart kink
Language: English
Status: Completed
Published: 2015-11-14
Updated: 2015-11-14
Packaged: 2018-05-01 13:45:22
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,477
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5208089
Author URL: https://archiveofourown.org/users/deviancy/pseuds/deviancy
Summary: <blockquote class="userstuff">
              <p>It's amazing what pleasure a heart can bring.</p>
            </blockquote>





	the rush that comes with your embrace

**Author's Note:**

> reader isn't frisk, just some girl that fell to the underworld 
> 
> i saw some body pillow of mtt and that's the exact version of him i'm using
> 
>  
> 
> [fill for the kink meme ](http://undertail.dreamwidth.org/256.html?thread=18176#cmt18176)

**i.**

Sometimes, it's good to be reminded that you don't have to be _living_ to be _alive_. 

 

**ii.**

When he takes you by the hand and calls you  _darling_  with that lilting sort of purr, leaning in with a sly smile, you can hardly believe a robot wants to take anyone to bed at all, let alone you.

But then you think: it's can't be that surprising, can it? That a robot that lives can feel and want, just like anyone else. After all, from all the friends you've made to all the monsters you've met-- you know that it's  _different_  here in the Underworld. There are skeletons that walk and talk and pun. There are goats that rule and flowers that whisper secrets breathed into cold air. 

And there are glorious, ethereal creatures that cup your chin and tilt it upwards, sealing his lips to yours, setting your knees to jello and quenching your hidden curiosities.

It's a surprise, but you intend to take full advantage.

 

**iii.**

Mettaton's chassis opens with a soft, pneumatic hiss and it's the most erotic thing you've ever _seen_. It looks almost obscene, the way his glass is pulled back, revealing with nothing save for the empty space where his heart should be.

He reaches inside himself to pull out his still thrumming heart, and you _squirm_ , biting your lip so hard that there's a tinge of copper on your tongue. As if it were nothing at all-- as if he were removing mere lingerie and dangling it before your eyes-- Mettaton graciously holds out his glowing heart. The smirk on his metal lips stretches wide as you gingerly take it with shaking hands and flushed cheeks. 

It's just as beautiful up close as it was enclosed in glass. 

Still covered in pink grease and  _warm_ , his heart pulsates in your hand. Flicking your gaze back to him, he's reclined on the pillows to drink in the sight of you as you hold this delicate metal organ more carefully than you'd hold your own. That same pink slick is trickling down his open chassis, coating his thighs and soaking the bed, and he runs his fingers along the seams of his plating, humming contentedly.

Turning back to the heart, you laugh fondly and a little bit wild, because you know this is a _gift_ , no matter how flippant he seems to be.  This is his sacrifice of vulnerability to _your_ altar, willingly given. If you wanted to, you could crush it in your fist, could use the force within you to ruin him in every way. You could break him, and the gravitas isn't lost on you.

Dizzy with lust, you cradle it close, ideas filling your head to the brim. You grin down him and it's sharp like razor-wire, possessive, if only for tonight.

After all: he's given this to  _you_. No one else.

When he gives you nothing but a lewd grin in return, you take it as permission.

 

**iv.**

With legs divine, he pulls you closer until you're perched on his lap, his smooth metal crotch to yours, pantyclad. His oil gets all over everything, your underwear included, and you can feel the air venting off his chest, cool and gentle. There is no mistaking him for anything but what he is, and maybe that's part of why you're so wet already.

Your eyes are heavy-lidded and his are too, anticipation crackling in the air. With reverence, you raise his heart to your mouth and lick a stripe up its metal exterior. Electricity crackles in your mouth. aThe taste of ozone is unmistakable. A small jolt travels straight up your spine and nests in your skull, and a rosy light sparks off its smooth surface, the glow stuttering if only for a second.

Despite yourself, a breathy moan escapes. It is foreign and it is _new_ , arousal like you've never felt before builds in your belly, like a hunger gnawing at you for _more_.

Mettaton, too, lets out a pleased sigh, laying a hand on your neck, thumb pressed to the hollow of it, waiting. 

It would be a shame to disappoint. 

 

**v.**

With both hands, you clutch his metal organ. After the first swipe of your tongue, the heart has been leaking an obscene amount of pink slick, coating your wrists and arms, evidence that gives his arousal away. You lick at the slick tentatively, and it's oil and it has a metallic tang and something smokey, plus that lightning-bright taste of the sparks that tickle your tongue.

It's so  _different_ from anything else you've ever done, but you don't hate it at all. With every careful lap, Mettaton seizes up, his limbs freezing in place for milliseconds as he tries to reconcile the data of your actions with the sensations of his heart, and his eyes roll back into the head. Part of him sparks, and he tells you not to worry as his voice goes fuzzy and full of static, keening and purring his pleasure all through it. He fists metal fingers into your hair and tugs your head back-- enough to hurt but in a good way-- and is, somehow, both disheveled and entirely too pleased.

And then Mettaton presses his lips to your skin, ghosting along your neck and down your collarbone, tracing the lines of it with his ridged grey tongue. Everywhere it goes, it leaves a trail of pink saliva on your skin, and it drips down your neck and down your shirt, caressing the subtle curve of your breasts. He follows it with his hands, pushing your shirt up to mouth at a nipple, and you almost drop his heart at the jolt you get from his mouth.

Not to be bested, you rub your fingers along the base of his heart, dragging your nails through the nearly invisible seams of it, and couple it with a teasing flick of the tongue. Mettaton lets out a startled moan, urging you to do it again, and his hands slide down your breasts, your ribs, and come to settle on your hips. So close to where you want him, but so far.

Everywhere he mouths at stings in that sweet pleasure-pain way, and true to form, the same goes for whatever you do with his whirring heart. 

He pulls your shirt off, and the heart lays in your lap for just a moment, cradled between your crotch and his. It's  _warm_ there, lightly vibrating, and-- you get an  _idea._

 

**vi.**

Half naked and exposed, you grow more eager in your attempts to consume him without consuming _all_ of him. There's a cool hiss of air as he has to vent from his chest again to release the mounting pressure, because you've rolled off of him to straddle his heart on the bed, legs folded beneath you. You grind against it with a heady moan, letting it rub against your bare clit, sparks tingling pleasantly against your pussy.

Mettaton shifts to curl around your back, chin hooked over your shoulder to watch with rapt attention, and he's all warm metal and beveled surfaces. He buries his face in the crook of your neck, leaving a sucking bite with perfect, too-sharp teeth. Shuddering, you redouble your efforts, relishing in the vibrations, and how well the slick takes to heat. Mettaton shivers with you, in a feedback loop of your design.

 To see him fall apart is your ambrosia.  

Behind you, you feel one of his hands caressing the seam of his chassis, but it is less to please himself than to cause more of that pink oil to spill, and with slicked up fingers, he reaches beneath you with an extended arm and just caresses your lips, and that's still enough to make you gasp in surprise, laughing all the while. Turning your head, you kiss him again, sharp and electric. When you manage to press some of the heart into your cunt it sends you both in a feedback loop of pleasure, and the vibrations are so much  _more_ once some of it's inside you. 

You try  _very_ hard not to come right then and there, toppling forward in a slump, face pressed to a pillow and panting.

Mettaton grins.

 

**vii.**

He's three fingers deep inside you, and you're clutching the sheets between your fingers. Your legs shake but you keep your ass in the air because it's _too good_ to let him stop now. Mettaton laps at your pussy eagerly, and takes great care to touch your clit every way you like. A thumb running along the underside with gentle tingling, his tongue suckling on it with those wild sparks, or just the fluttering, teasing that's so good you might cry.

And, too, he keeps adding fingers, so much larger than yours. The three push in and out of you with a gentle speed, and the fourth goes on so easy, even if you do feel the stretch. You whine, and Mettaton laughs softly, kissing the inside of your thigh. In your hands, still, is his heart, still somehow wet with rose colored oil. You spend your time mostly licking at it lightly at his request, because darling, he's got something  _special_ he wants to do.

While you think it's his cock, you haven't noticed a place for it to emerge from his metal body. He is the embodiment of glamorous perfection, sexualized out of his own choice. 

The thought is lost as he resumes eating you out with vigor. You feel so electrified; every taste and touch sends a delightful buzz up your spine, adding to your pleasure. Your thighs are damp with your own arousal, and you've come at least twice so far, and a third looms closer, like a rising tide coming in, slowly but surely. He fucks you and curls his fingers just so to find that place to _rub_ that sends you off the rails, coupled with a long suck of your clit, tongue caressing the underside of it.

You break like a dam, spasming around his tongue and fingers, riding it out with broken sounds. There are tears in your eyes, but the good kind. You've met oblivion and seen its edge, and this is it.

As soon as it's over, when you're boneless and loose again, with all your muscles relaxed-- Mettaton slides his thumb in. You've never been fisted before, but it's a strange feeling, if a pleasant one. You can feel every metal knuckle, every little flex. When you caress his heart, you can feel his hand shake  _inside_ of you, and oh, you like that.

But you don't get long to relish it.

He asks, every so sweetly, for his heart back.

Oh.

_Oh._

 

**viii.**

Despite appearances, Mettaton's heart is nearly the size of two of your fists put together. He's in control, now, because he's the one with the heart in hand. You're on your back, now, so you can watch him as his heart slides into you. He coats it liberally with all that pink slick of his, more than it produced on its own, his other hand still fingering you with ease. 

You are not entirely certain it will fit, but you want it more than anything. This offering to you, a way to connect with him in a way that few others have, if any.

Mettaton coaxes you with a purr, his closed fist sliding in and out at a languid pace, filling you with shock-waves of sweet agony, the pressure overwhelming. You could die now and be trapped in this moment eternal, and you'd be happy.

But you do not, and it is time. 

He withdraws his hand, inch by inch, leaving you a panting, gaping mess. The heart in his hand looks as though it might not ever fit, but you're both  _determined_. The first curve goes in first, and it sparks more than ever before, sending visible arcs of rose tinted electricity across your skin, and you can't contain a near scream, thrashing in a fit of  _yes god more I need it so good_. He leans over to kiss you and bite at your lip, the resulting copper-tang just as much for you as it is for him.

The bottom of the heart goes in next, shifting it inside of you, and it's so strange to be able to  _hear_ it-- and more than that?

You see the glow _beneath_ your skin. Mettaton grins and asks if you're ready, and you're not but you'll never be but you're  _excited_ , and say just that and-- in it goes, the last side, the last rounded corner, the last piece of him  _inside_ of you, and you can tell it's taking a toll on him as well. You lean up to kiss him, but also twist at his dial, to touch his still-open chassis, intent on reducing him into a pleasured mess. You've never felt so full before, and with every tensing of your muscles, it slides deeper into you,the heart outline traveling up your belly. Mettaton's eyes roll back into his skull, and his arms lock up so much that he collapses against your bare chest, spasming every time he lets out a shuddering moan. 

Eagerly, you slide two fingers into his mouth, scissoring them and caressing his tongue, and consciously try to  _squeeze_ just to wring out another reaction from him, and it  _works_. He's talking, now, and it's strings of garbled code and gibberish, stilted and off-kilter, talking faster and faster each time you try. You rub your belly where the heart is, pressing down  _hard_ on it, to massage it through your skin, and squeeze your muscles at the same time.

He lets out a beleaguered  _yowl_ , and promptly collapses entirely, boneless and knocked out, a full overload of Mettaton's systems now complete. The vent on his chest and beneath his shoulder armor work over time as he reboots, and you turn down his dial to what it was before, not entirely certain what its purpose was, but it certainly seemed to please _him_.

And that's all that matters, isn't it?

Looking down at him, you've never felt so sated. You're loathe to let go of the heart, in all honesty-- but all good things must come to an end. _  
_

 

**vix.**

After one lengthy extraction later, a lengthier attempt to gather the remains of your clothes, and an even lengthier exchanging of UnderNet names and cellphone numbers, you make plans for _next time_ and finally take your leave. Covered in hickeys and still smelling a little bit ozone-sharp, you make your way out of the CORE, and your head hasn't quite left Mettaton's bed.

Going through the lobby and out the front door, you realize this might count as a walk of shame, but...

That would imply you were ashamed at all.

**Author's Note:**

> man, this is so far from what i normally write


End file.
